The screenshot is of the extensions page and features an entry for an extension titled "Google Drive (by Google)", with an attached description of "Save web content to Google Drive".
This is one of the first pieces of firm proof beyond rumour that indicates that the Google Drive is truly in development and will be launched soon.
Since the extension is used for clipping web content to the Google Drive it seems that the 'GDrive' will likely be a combination of advanced bookmarking of web content as well as used for storing traditional desktop files. This makes sense, since files are required by enterprise for legacy reasons but unifying an interface for web content (cloud documents) and traditional files and folders would ease the transition from files to the cloud.
Doing a little more digging reveals that the extension was first referred to by a Googler in August 2011 here so the extension has been in testing for some time, perhaps we could expect a Summer launch marking one year after they started testing internally? Let us know your predictions in the comments below!
Bonus: The window in this screenshot doesn't feature a minimize button, what kind of a system could this Googler be running on? Perhaps an advanced version of ChromiumOS with window management..? Let us know your thoughts in the comments below!